Add BOARD_INIT_BOOT_IMAGE_PAGESIZE

This allows partners to configure the pagesize flag to mkbootimg while
creating the init_boot.img.
The pagesize flag is only used for the padding of the image itself which
is managed in the bootloader.

Flag: EXEMPT bug fix
Test: m # with this defined in cuttlefish
Bug: 411213637
Change-Id: I48da7722c68e3bf3af9ab5af9cff19a11b0820eb
diff --git a/core/Makefile b/core/Makefile
index cf1e13a..f6891e3 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1543,8 +1543,14 @@
 
 INTERNAL_INIT_BOOT_IMAGE_ARGS := --ramdisk $(INSTALLED_RAMDISK_TARGET)
 
-ifdef BOARD_KERNEL_PAGESIZE
-  INTERNAL_INIT_BOOT_IMAGE_ARGS += --pagesize $(BOARD_KERNEL_PAGESIZE)
+ifdef BOARD_INIT_BOOT_IMAGE_PAGESIZE
+	INTERNAL_INIT_BOOT_IMAGE_PAGESIZE := $(BOARD_INIT_BOOT_IMAGE_PAGESIZE)
+else ifdef BOARD_KERNEL_PAGESIZE
+	INTERNAL_INIT_BOOT_IMAGE_PAGESIZE := $(BOARD_KERNEL_PAGESIZE)
+endif
+
+ifdef INTERNAL_INIT_BOOT_IMAGE_PAGESIZE
+  INTERNAL_INIT_BOOT_IMAGE_ARGS += --pagesize $(INTERNAL_INIT_BOOT_IMAGE_PAGESIZE)
 endif
 
 ifeq ($(BOARD_AVB_ENABLE),true)